Alaska Extended Forecast Discussion
NWS Weather Prediction Center College Park MD
626 PM EDT Sat Oct 30 2021
Valid 12Z Wed Nov 03 2021 - 12Z Sun Nov 07 2021
...Overview and Model Guidance...
A complex stormy weather pattern with potent offshore storms will
continue to affect portions of Alaska next week. The flow will
feature several potent Bering Sea, Arctic, and Gulf of Alaskan
surface lows rotating within energetic/closed mean upper troughs
over these areas and around the periphery of an amplified western
Canada to Interior mean upper ridge. Guidance continuity and
variance with embedded features remains less than stellar
throughout medium range time scales, but a blend of best clustered
guidance from the 12 UTC GFS/ECMWF with the GEFS/ECMWF ensemble
means (that do have compatible larger scale pattern evolutions)
and the 19 UTC National Blend of Models (except QPF/PoPs) again
does offer a seemingly reasonable solution that maintains decent
WPC product continuity when weighting shifts increasingly from the
higher resolution models that offer more detail consistent with
higher predictability for days 4/5 (Wednesday/Thursday) and then
quickly shifting main focus to the ensemble means as
predictability quickly decreases into days 6-8 (Friday-next
weekend).
...Weather/Hazard Highlights...
An extratropical low partially associated with recent western
Pacific Typhoon Malou should rotate across the northern Gulf of
Alaska Wednesday/Thursday. This offers some threat for maritime
interests and inland as heavy precipitation works from southeast
through southern Alaska and the AKpen/Kodiak Island. Additional
storm systems will also this period work over the Bering Sea as a
maritime threat and combine with energies lifting on the western
periphery of an amplified Interior upper ridge position to spread
enhanced winds/precipitation across the region and into western
Alaska. In this pattern, the central and eastern Interior through
the North Slope should enjoy much above normal readings next week,
with many locals more than 20 degrees above normal. Deep energy
digging underneath into the Gulf of Alaska later next week into
next weekend also presents a favorable environment for storm
genesis with amplified/closed upper trough development to present
a multi-day maritime and southern/southeastern coastal threat.
Schichtel
Additional 3-7 Day Hazard Information can be found on the WPC
medium range hazards outlook chart at:
https://www.wpc.ncep.noaa.gov/threats/threats.php
WPC medium range Alaskan products including 500mb, surface
fronts/pressures progs and sensible weather grids can also be
found at:
https://www.wpc.ncep.noaa.gov/alaska/ak_5dayfcst500_wbg.gif
https://www.wpc.ncep.noaa.gov/alaska/akmedr.shtml
https://www.wpc.ncep.noaa.gov/alaska/ak_5km_gridsbody.html